feat(epic2): Implement core authentication and authorization services

- Implement Audit Service (2.5)
  - gRPC server with Record and Query operations
  - Database persistence with audit schema
  - Service registry integration
  - Entry point: cmd/audit-service

- Implement Identity Service (2.2)
  - User CRUD operations
  - Password hashing with argon2id
  - Email verification and password reset flows
  - Entry point: cmd/identity-service
  - Fix package naming conflicts in user_service.go

- Implement Auth Service (2.1)
  - JWT token generation and validation
  - Login, RefreshToken, ValidateToken, Logout RPCs
  - Integration with Identity Service
  - Entry point: cmd/auth-service
  - Note: RefreshToken entity needs Ent generation

- Implement Authz Service (2.3, 2.4)
  - Permission checking and authorization
  - User roles and permissions retrieval
  - RBAC-based authorization
  - Entry point: cmd/authz-service

- Implement gRPC clients for all services
  - Auth, Identity, Authz, and Audit clients
  - Service discovery integration
  - Full gRPC communication

- Add service configurations to config/default.yaml
- Create SUMMARY.md with implementation details and testing instructions
- Fix compilation errors in Identity Service (password package conflicts)
- All services build successfully and tests pass

services/audit/internal/api/server.go

@@ -0,0 +1,125 @@
+// Package api provides gRPC server implementation for Audit Service.
+package api
+
+import (
+	"context"
+
+	auditv1 "git.dcentral.systems/toolz/goplt/api/proto/generated/audit/v1"
+	"git.dcentral.systems/toolz/goplt/services/audit/internal/service"
+	"go.uber.org/zap"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+// Server implements the AuditService gRPC server.
+type Server struct {
+	auditv1.UnimplementedAuditServiceServer
+	service *service.AuditService
+	logger  *zap.Logger
+}
+
+// NewServer creates a new Audit Service gRPC server.
+func NewServer(auditService *service.AuditService, logger *zap.Logger) *Server {
+	return &Server{
+		service: auditService,
+		logger:  logger,
+	}
+}
+
+// Record records an audit log entry.
+func (s *Server) Record(ctx context.Context, req *auditv1.RecordRequest) (*auditv1.RecordResponse, error) {
+	if req.Entry == nil {
+		return nil, status.Error(codes.InvalidArgument, "entry is required")
+	}
+
+	entry := req.Entry
+
+	// Convert proto entry to service entry
+	serviceEntry := &service.AuditLogEntry{
+		UserID:     entry.UserId,
+		Action:     entry.Action,
+		Resource:   entry.Resource,
+		ResourceID: entry.ResourceId,
+		IPAddress:  entry.IpAddress,
+		UserAgent:  entry.UserAgent,
+		Metadata:   entry.Metadata,
+		Timestamp:  entry.Timestamp,
+	}
+
+	// Record the audit log
+	if err := s.service.Record(ctx, serviceEntry); err != nil {
+		s.logger.Error("Failed to record audit log",
+			zap.Error(err),
+			zap.String("user_id", entry.UserId),
+			zap.String("action", entry.Action),
+		)
+		return nil, status.Errorf(codes.Internal, "failed to record audit log: %v", err)
+	}
+
+	return &auditv1.RecordResponse{
+		Success: true,
+	}, nil
+}
+
+// Query queries audit logs based on filters.
+func (s *Server) Query(ctx context.Context, req *auditv1.QueryRequest) (*auditv1.QueryResponse, error) {
+	// Convert proto filters to service filters
+	filters := &service.AuditLogFilters{
+		Limit:  int(req.Limit),
+		Offset: int(req.Offset),
+	}
+
+	if req.UserId != nil {
+		userID := *req.UserId
+		filters.UserID = &userID
+	}
+	if req.Action != nil {
+		action := *req.Action
+		filters.Action = &action
+	}
+	if req.Resource != nil {
+		resource := *req.Resource
+		filters.Resource = &resource
+	}
+	if req.ResourceId != nil {
+		resourceID := *req.ResourceId
+		filters.ResourceID = &resourceID
+	}
+	if req.StartTime != nil {
+		startTime := *req.StartTime
+		filters.StartTime = &startTime
+	}
+	if req.EndTime != nil {
+		endTime := *req.EndTime
+		filters.EndTime = &endTime
+	}
+
+	// Query audit logs
+	entries, err := s.service.Query(ctx, filters)
+	if err != nil {
+		s.logger.Error("Failed to query audit logs",
+			zap.Error(err),
+		)
+		return nil, status.Errorf(codes.Internal, "failed to query audit logs: %v", err)
+	}
+
+	// Convert service entries to proto entries
+	protoEntries := make([]*auditv1.AuditLogEntry, 0, len(entries))
+	for _, entry := range entries {
+		protoEntries = append(protoEntries, &auditv1.AuditLogEntry{
+			UserId:     entry.UserID,
+			Action:     entry.Action,
+			Resource:   entry.Resource,
+			ResourceId: entry.ResourceID,
+			IpAddress:  entry.IPAddress,
+			UserAgent:  entry.UserAgent,
+			Metadata:   entry.Metadata,
+			Timestamp:  entry.Timestamp,
+		})
+	}
+
+	return &auditv1.QueryResponse{
+		Entries: protoEntries,
+		Total:   int32(len(protoEntries)), // Note: This is a simplified total, actual total would require a count query
+	}, nil
+}